In most optical imaging and projection systems, the optical elements are arranged in series along a single optical axis. Some systems, however, use arrays of lenses arranged side by side. The best-known arrangement of this sort is the “fly's eye” lens array, which is generally used to achieve uniform irradiance in projection optics.
Lens arrays are also used in some imaging devices. For example, U.S. Pat. No. 7,700,904, whose disclosure is incorporated herein by reference, describes a compound-eye imaging device, which comprises nine optical lenses arranged in a matrix array of three rows and three columns, and a solid-state imaging element for capturing unit images formed by the optical lenses. A stray light blocking member having a rectangular-shaped window is provided on the capture zone side of the optical lenses to block incident lights in a range outside each effective incident view angle range of each optical lens.
In general, the optics used in an imaging device are designed to form a single image on an image sensor. In some applications, however, multiple images may be superimposed. Such a scheme is described, for example, by Marcia et al., in “Superimposed Video Disambiguation for Increased Field of View,” Optics Express 16:21, pages 16352-16363 (2008), which is incorporated herein by reference. The authors propose a method for increasing field of view (FOV) without increasing the pixel resolution of the focal plane array (FPA) by superimposing multiple sub-images within a static scene and disambiguating the observed data to reconstruct the original scene. According to the authors, this technique, in effect, allows each sub-image of the scene to share a single FPA, thereby increasing the FOV without compromising resolution.
Various methods are known in the art for optical 3D mapping, i.e., generating a 3D profile of the surface of an object by processing an optical image of the object. This sort of 3D map or profile is also referred to as a depth map or depth image, and 3D mapping is also referred to as depth mapping.
Some methods of 3D mapping are based on projecting a laser speckle pattern onto the object, and then analyzing an image of the pattern on the object. For example, PCT International Publication WO 2007/043036, whose disclosure is incorporated herein by reference, describes a system and method for object reconstruction in which a coherent light source and a generator of a random speckle pattern project onto the object a coherent random speckle pattern. An imaging unit detects the light response of the illuminated region and generates image data. Shifts of the pattern in the image of the object relative to a reference image of the pattern are used in real-time reconstruction of a 3D map of the object. Further methods for 3D mapping using speckle patterns are described, for example, in PCT International Publication WO 2007/105205, whose disclosure is also incorporated herein by reference.
Other methods of optical 3D mapping project different sorts of patterns onto the object to be mapped. For example, PCT International Publication WO 2008/120217, whose disclosure is incorporated herein by reference, describes an illumination assembly for 3D mapping that includes a single transparency containing a fixed pattern of spots. A light source transilluminates the transparency with optical radiation so as to project the pattern onto an object. An image capture assembly captures an image of the pattern on the object, and the image is processed so as to reconstruct a 3D map of the object.